I'm an employee in a BPO company since May 2018. From June-December 2018 I've been getting night differential pay, but this January-March, they stopped paying me that night differential pay. So I asked the accounting/finance and I was surprised because they're telling me that it's a package part of my basic pay. So I checked my contract again though I'm confident that it's not what it is that they're telling me. It's never there saying that my basic pay is night differential inclusive. Advise please.